I. Field of the Invention
This invention relates generally to surgical instruments, and more particularly to a device for creating holes of a predetermined depth into body tissue.
II. Discussion of the Prior Art
In conducting various surgical procedures, it often becomes desirable to form a hole of a given diameter through tissue in such a way that the depth of penetration can also be accurately controlled. A procedure referred to as transmyocardial revascularization (TMR) may be applied endocardially or epicardially in revascularizing ischemic tissue. Here, small holes are drilled in the myocardium to allow blood to reach areas of the heart normally served by arteries or arterioles but which may have become occluded due to coronary artery disease. Also, where an artery has become so obstructed that a guide wire commonly used in percutaneous transluminal coronary angioplasty procedures cannot be passed, a need exists for an instrument to bore through the stenotic lesion in a controlled fashion so that the affected artery is not perforated.
Instruments especially designed for carrying out atherectomy procedures in larger arteries generally involve a catheter supporting a rotatable cutting blade on a distal end thereof for cutting through stenotic lesions and with suction being applied to remove the debris created during the cutting procedure. Generally speaking, the depth of penetration is controlled strictly by the operator in advancing the catheter. The instrument itself has no built-in structure for controlling the depth of penetration.
A need therefore exists for a surgical instrument that can safely be used in either open surgical procedures or in laparoscopic or intravascular procedures to create a hole of a predetermined diameter and desired depth dimension in multiple incremental uniform steps in target tissue structures.